docs: def copy_file(self, path, prefixed_path, source_storage):
          """
          Appends path to task queue if threads are enabled, otherwise copies
          the file with a blocking call.
          """
          args = (path, prefixed_path, source_storage)
          if settings.threads:
              self.tasks.append(args)
          else:
              self.do_copy_file(args)